Bridge wall



2 Sheets-Sheet 1.

A. SNELL.

'(No Model.)

BRIDGE WALL.

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2 Sheets-Sheet 2. A. SNELL.

BRIDGE WALL.

(No Model.)

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il'nirnn dramas ANTHONY SNELL, OF ROCHESTER, NEW YORK.

BRIDGE-WALL.

SPECIFICATION forming part of Letters Patent No. 369,564,.datedSeptember 6, 1887.

Application filed May 20, 1887. Serial No. 238,813. (No model.)

To (ZZZ whom, it may concern.-

Be it known that I, ANTHONY SNELL, of Rochester, in the county of Monroeand State of New York, have invented anew and usefulImprovementinBridgeails,whichimprovement is fully set forth in thefollowing speciiication and shown in the accompanying drawings.

The object of my invention is to produce an improved bridgewa-ll for asteam-boiler furnace, the same being hereinafter fully de scribed, andmore particularly pointed outin the claim.

Referring to the drawings, Figure 1 is a side elevation of a portion atthe front end of a furnace for a horizontal steanrboiler, a part of theside wall being broken out to uncover the bridge-wall, the latter beingvertically scc tioned at the top, as on the dotted line min Fig. 2, andat the bottom, as on the dottedline 3 Fig. 2, a front elevation of thebridge-wall, the side walls of the furnace, the boiler, and grate beingvertically sectioned, as on the dotted line 2 in Fig.1, a part ofthefront wall of said bridge-wall being removed to expose the cavitytherein; Fig. 8, a side elevation of afurnace, showing another formofbridge-wall, the view being similar to that shown in Fig. 1, a part ofthe side wall being broken out and the bridge-wall being in partvertically sectioned, as on the dot-ted line :0 in Fig. 5, and viewed asindicated by the arrow pointed thereon; Fig. 4, a sectional elevation ofa portion of the bridge-wall, seen as inFig. 3 and sectioned by the sameplane, drawn to alarger scale to better show the damper, the latterbeing shown in two positions by full and dotted lines; Fig. 5, atransverse section of the furnace and other parts, taken as on thedotted line y in Fig. 8, and viewed as indicated by the arrow pointedthereon, the figure showing a view of the rear side of the bridge-wall;Fig. 6, a vertical section ofa portion of the bridgewall, seen in thedirection in which Figs. 3 and 4c are seen, said wall and a portion of agrate being sectionedas on the dotted line 2 in Fig. 5; and Fig. 7, aview of the bridgewall and parts associated therewith, seen as indicatedby arrow at in Fig. 5, the walls being horizontallysectioned, as on thedotted line y in Fig. 5.

Referring to the parts, A is the furnace for a horizontal steam-boiler,B, 0 being the side walls of the furnace, 1) the grate,.and E thecast-iron front thereof, allsubstantially of common form.

F is the transverse bridge-wall at the rear of the furnace, the form ofwhich wall constitutes the novelty of my invention. The essentialfeature is that the wall is hollow vertically, for the purpose ofadmitting air with its full supply of oxygen to the flame from the fire,for the double purpose of effectinga more complete combustion and ofdriving the flame against the boiler-sheets. Two forms of my improvedbridgewall areshown. Thatshown in Figs. 1 and 2 is the form I build whena new boiler, arch, or furnace is constructed. The form shown in Figs. 3to 7 represents the bridge-wall when built into an old furnace or boilerarch. The combustion being more perfect when my hollow bridge-wall isused enables me to shorten up or reduce the grate-surface. On thisaccount, when I build a new furnace I use shorter grates, as shown inFig. 1, and when I build a new bridge-wall in an old arch I build itupon the ends of thegrates, as shown in Fig. 3, thus reducing the lengthof the original gratesurface.

The bridge-wall is built with firebrick and formed with an internalvertical cavity, a, which, in the form shown in Fig. 1, extends from thebottom to the top of the bridge-wall, while in the form shown in Fig. 3it extends only part way of the height of said wall, the latter beingmade solid above and below said cavity. In either case the openings ofthe cavity are respectively below and above the level of the grate. InFigs. 1 and 2 the inletopening I) for the air below the grate is shownformed with an arched top, free passages being given to the air upthrough the bridge-wall to the flame beneath the boiler. The inflowingair passes through draft-openings in the iron front E of the furnace andthrough the archway b. (Plainly indicated by arrows.)

In the form shown in Fig. 3 the opening 1) below the grate is a simplerectangular opening of suitable size; or it may be a horizontal row ofopenings formed by omitting alternate bricks from the front part of thebridge-wall when the latter is being: built. In this form also thecavity a opens out into the space Gin the rear of the bridgewall throughopenings 0,

ICO

formed in the rear part of said bridge-wall. From these openings 0 theair flows upward along the rear surface of the wall to the flame beneaththe boiler, as in the ease of the other form described.

In the form shown in Fig. 3 the air entering the opening I) flows upwardthrough between the grate-bars and out at the openings 0, (clearlyindicated by arrows in Fig. 4,) said air primarily entering beneath thegrate through the iron furnace-front, as in the first instance.

I sometimes find it convenient, in addition to the openings 0, to addvertical air-passages d to the rear side of the bridgewall, forming saidpassages so as to communicate by means of openings 6 with the cavity a,as clearly shown in Fig. 6. These air-passages tend to direct thecurrents of air more certainly upward to the flame.

A simple damper, f, in the form of a flat bar placed horizontally in thecavity a upon bearings at its respective ends, serves to regulate theflow of airupward throughthe bridgewall. Ahandle, G uponthe outside ofthe side wall of the fu rnace, rigid with the damper, enables theattendant to adjust the damper as may be required.

The fresh air from without, being conducted into the flame at the top ofthe bridgewall,

supplies oxygen for a more complete combustion of the accompanying smokeor unburned carbon, thus adding to the intensity of the heat under andaround the boiler. Besides, the currents of air rushing upward tend todrive the flame more closely against the boiler-sheets, and thusincrease the generation of steam Within.

The bridge-wall, as shown in Fig. 1, is formed with a horizontal ledge,h, along its front face, projecting forward to receive and hold the rearends of the grate-bars. Theforward ends of said bars rest on a similarledge, 2', cast in the usual manner on the inner face of theiron frontE.

What I claim as my invention is- In combination with a steam-boilerfurnace and fire-grate therefor, a hollow transverse bridge-wall formedwith openings in the front side thereof, below said grate, communicatingwith the cavity in said bridge-wall, and vertical air passages on therear side of said bridge-walhsaid passages communicating with saidcavity within said bridge-wall, substantiall y as shown and described.

ANTHONY SNELL.

Witnesses:

E. B. WHITMORE, M. L. MODERMOTT.

